You searched for: “pejoration
amelioration, melioration, pejoration
amelioration (uh meel" yuh RAY shuhn) (noun)
A making or becoming better; improvement: Efforts of amelioration are being made for the suffering of people who have lost their jobs.
melioration (meel" yuh RAY shuhn; mee" lee uh RAY shuhn) (noun)
1. The act or process of improving something or the state of being improved: The workers are hoping for a melioration of the financial situation for their company.
2. The linguistic process by which a word over a period of time grows more elevated in meaning or more positive in connotation: The word "nice" has gone through the process of melioration because it formerly meant "foolish".
pejoration (pej uh RAY shuhn; pee" juh RAY shuhn) (noun)
1. The process or condition of worsening or degenerating; deterioration: The global financial situation is going through a process of pejoration.
2. The process by which the meaning of a word becomes negative or less elevated over a period of time: The word "silly", which formerly meant "deserving sympathy, helpless, or simple", has gone through pejoration, resulting in the meanings of "showing a lack of good sense, frivolous".

Some would say that the process of the melioration of English vocabulary is balanced with the process of pejoration, because words become more elevated in meaning; while other words become less so; however, the amelioration of the situation is helped by the use of new dictionaries.

pejoration (pej" uh RAY shuhn)
1. A worsening deterioration, or decline in quality, status, or value.
2. Made more scornful, despised, disdainful, disrespectful, or contemptuous.
3. A change over time in the meaning of a word so that it becomes less favorable or more negative; for example, the English word "cunning" formerly meant "learned" but now it is used to mean "cleverly deceitful".
4. Semantic changes in words to a lower, less approved, or less respectable meaning.
5. In linguistics, a change of meaning for the worse; the process by which the meaning of a word becomes negative or less elevated over a period of time; such as, silly, which formerly meant "deserving sympathy, helpless or simple," has come to mean "showing a lack of good sense, frivolous".
6. Changes over time in the meanings of words so that they become less favorable or more negative.

An example is the English word cunning, formerly used to mean "learned" but now it is used to mean "cleverly deceitful".